Neuroleptics are among the most widely prescribed psychotropic drugs. But these drugs are also associated with troublesome adverse effects, of which movement disorders are probably the most serious ones in terms of frequency, persistence, and overall impact on the well-being of patients and caregivers. Neuroleptic-induced movement disorders include extrapyramidal symptoms (EPS) and tardive dyskinesia (TD). These side effect tend to be much more common and also more problematic in older than in younger patients. The newer atypical antipsychotic drugs have a lower risk of EPS and probably of TD. Nonetheless, the atypical antipsycotics are not entirely free of the risk of inducing movement disorders. Furthermore, the newer antipsychotics are considerably more expensive than the typical ones- an increasingly important consideration in these days of managed care. Our studies to date have shown that a majority of psychiatric patients over age 45 treated with conventional neuroleptics, even at low dosages, develop acute EPS. The cumulative annual incidence of TD in this population is 29%, which is six times greater than that reported in younger adults. However, the risk of EPS and TD with the atypical agents has not been documented in longitudinal research, especially that involving older patients, and done primarily without pharmaceutical industry support. We propose to study the incidence of and risk factors (including instrumentally detected motor abnormalities and neuropsychological deficits) for EPS and TD associated with the three most commonly used atypical antipsychotics (risperidone, olanzapine, and quetiapine) among middle-aged and elderly psychiatric patients. Additionally, we propose to examine the potentially positive influence of the three atypical agents on pre- existing neuroleptic- induced TD. Finally, we will explore the impact of movement disorders on everyday functioning and quality of life. We believe that our findings will have major therapeutic implications for the use of antipsychotics, particularly in older patients.